Vehicle Window Washer Control Using Timing Compensation
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Solution Overview
Problem
Existing window-washing systems for vehicles require customization for each vehicle model, leading to high development costs and insufficient precision in spraying the washing liquid at the desired location on the glazed surface due to delays from inertia and hydraulic architecture.
Innovation Solution
A method and module for controlling the window-washing system that advances the initiation of spraying by a compensation period accounting for liquid feeding time and potentially electrical processing delays, with adjustments based on vehicle conditions such as speed, temperature, and dirtiness, to ensure precise and continuous spraying over defined angular sectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the spraying control is based on angular position of the wiper-blade arm, then the spraying can be delivered at predefined zones, but the precision of spraying location is insufficient due to system delays
Solution Approach 1:
The control system advances the initiation of spraying by a compensation period that accounts for liquid feeding time from the reservoir to the nozzle and electrical processing delays. This preliminary action ensures that the liquid arrives at the desired location on the glazed surface exactly when needed, compensating for the inherent time delays in the hydraulic and electronic systems.
2Ease of operation
If a cam and shoes are used to control spraying based on drive shaft angular position, then spraying control is achieved, but the system requires customization for each vehicle model increasing development costs
Solution Approach 1:
The patent replaces model-specific cam profiles with a universal electronic control system that uses a lookup table storing angular position data for multiple vehicle models. The control unit automatically selects the appropriate data based on the detected vehicle model, allowing the same hardware to serve multiple vehicle types without customization.
Solution Approach 2:
The mechanical cam and shoe system is replaced with an electronic control system that uses a sensor to detect the angular position of the wiper-blade arm and a control unit to process this information. This substitution eliminates the need for physical customization while maintaining precise spraying control.
3Reliability
If the spraying zone is determined to ensure effective cleaning, then cleaning performance is improved, but the system fails to account for liquid feeding time causing imprecise spraying
Solution Approach 1:
The control system initiates spraying in advance by a compensation period that includes the time required for liquid to travel from the reservoir to the nozzle. This ensures that the liquid is already at the nozzle when the wiper blade reaches the desired zone, maintaining both cleaning effectiveness and spraying precision.
Data Source
AI summary
The present invention relates to the control of a window washer system associated with a system for wiping a glazed surface of a motor vehicle, said wiper system comprising a wiper motor for rotating at least one wiper blade holder arm, and this window washer system comprising a liquid reservoir connected to at least one nozzle designed to deliver, over a wiping cycle, at least one liquid jet for at least a first window washer system activation period defined between an instant (td1) for initiating the spraying of the liquid and an instant (ta1) for stopping the spraying of the liquid, these instants each being determined as a function respectively of a first angular position and of a second angular position of the wiper blade holder arm defining a first angular sector in which the spraying of the liquid is continuous. According to the invention, the instant (td1) for initiating the spraying is advanced by a compensation period (t1) corresponding at least to the period for feeding the liquid from the reservoir to the nozzle.